Device for exerting a constant returning torque on a rotatively movable unit



P! 16, 1946- c. H. H. RODANET 8, 48

DEVICE FOR EXEERTING A CONSTANT RETURNING TORQUE ON A RQTATIVELY MOVABLE UNIT Filed Oct. 22, 1940 2 Sheets-Sheet 1 Fiel.

- INV Nit, CHARLES HILAIRE HENRI an DANET.

I I 2 2 3 "rlfi ATTORNEYS Apnl 16, 1946. c. H. H. RODANET I DEVICE FOR EXERTING A CONSTANT RETURNING TORQUE ON A ROTATIVELY MOVABLE UNIT Filed Oct. 22, 1940 2 Sheets-Sheet 2 Fici.

3 INVENTOR CHARLES HILA RE'HENRI RODANET Frail.

as %N Patented Apr. 16, 1946 v am DEVICE FOR EXERTING A. CONSTANT RE- TURNING TORQUE ON A ROTATIVELY MOVABLE UNIT Charles Hi-laire Henri Rodanet, Neuill'y-sur Seine, France; vested in the AlienProp'erty Custodian Application October 22, 1940, SerialNTo. 362,229

In France December 11, I939 4 Claims.

Numerous apparatus exist which compris a rotatably movable unit, as is the case for instance with most measuring apparatus, and in which it isnecessary to permanently exert on said movable unit a returning torque as constant as possible. This problem has been solved up to now, by the use of springs, which are terisioned by the movable unit when the latter moves away from its zero abutment, and which, consequently, always tend to restore said unit towards said abutmerit. But the returning torque exerted by such springs is not constant, as it increases in proportion with the rotation of the movable unit; and this inconvenience is so much the more intense as the rotation of the movable unit can take place through a larger angle. 1

Thepresent invention is intended to solve the problem of exerting a constant returning torque ona rotatively movable unit. For that purpose, it consists in the new application, to" movable units of this type, of all known devices, used up to the present, as prime-movers, capable of exerting on a rotor the desired constant torque, without however preventing said rotor from having a movement,-under another influence, diiferent' from that which must be imparted thereto bythe aforementioned constant torque. Torque generators of this type are characterised, as re- By way of example, the combination of a definite type. of torque generator will be described, which is already known in. electric meters, with a measuring instrument such as an altimeter having a motion multiplying transmission mechanism, and in which, consequently; the amplitude of rotation of the last element of the mechanism is considerable. It is moreover to be noted that, in cases" of this kind, it is important that the. constant returningtorque should be exerted on the last movable element; by this means, in

I fact, the influence, of play is completely elimigards their function, by the double property of i exerting on the rotor a constant torque and of allowing the positive or negative sliding of the rotor.

Whereas, up to now, torque generators of this kind wereused as prime-movers, that is to say :1

for rotatably driving the rotor, they are on the contrary, according to the invention, applied to the production of a returning torque (therefore an antagonistic torque) on a rotor belonging to another driving system, which can, for instance, be that of a measuring instrument.

The constant torque generator can be of any type whatever as well as the driving system actuating the rotor; the invention does not reside, in fact, in either of these two known means, but rather in the new application of the first of said means, by combining it with the second in I such manner that its function is reversed. Whereas, in fact, up to now, said first means (the torque generator) served to rotatably drive a rotor, it is now antagonistic to said rotation, and this in order to produce the new industrial result which consists in obtaining the constancy of the returning torque exerted on a movable unit, whatever may be the amplitud of the rotation of said unit.

nated, said play being constantly taken: up by the action of'the returning torque.

The accompanying drawings illustrate, by way of example only, a form of construction of an altimeter improved according toth invention.

Fig. 1 is an explanatory diagram of the invention, in perspective view;

Fig. 2 is a cross section of one pole of the diagram. of Fig. l. I

Fig. 3 is an elevation view seen from the rear of the improved altimeter.

Fig. 4 is a side view looking in the direction of the arrowsIV-IV of Fig. 3. V

It is known that in certain electric meters (Figs. 1 and 2) the driving member iscenstituted' by a conducting disc I" preferably of high conductibility, for instance made of red" copper or aluminium, arranged between the poles of one or mor electromagnets 2.

The flux of each electromagnet is rendered asymmetric owing'tothe fact that a part of each pole 3" is embraced' by a conducting ring or small plate l' for instance made' of red copper, which has the effect of offsetting, in the corresponding parts, the magnetic flux.

It is known that in these conditions the direction of rotation of the movable disc I is such that it drives the current elements induced in said disc, from the normal flux towards the outof-phase flux.

Such a device comprising no sliding contact allows, without causing braking, of obtaining a constant returning torque exerted on the shaft 5, and consequently, of taking up all the play of the elements of a transmission connected to said shaft.

For preventing the inducing device from exerting any magnetic attraction on the movable magnetic members of the apparatus, it is advantageous to construct this inducing system symmetrically, by providing for instance two electromagnets 2 symmetrical relatively to the shaft 5 as shown in Fig. 1.

or discs 4*, as in the general arrangement of Figs.-

1 and 2, symmetrically relatively to the spindle 8 which carries the conducting. disc I? corre-' sponding to disc I of Figs, 1 and 2; The spindle 8 on which disc i is mounted constitute the last element of the motion transmission mechanism interposed between the aneroid capsules 9 and the pointer of the altimeter. These capsules, combined in the known manner, are secured at In on a bracket H carried by th plate I. The last capsule or free capsule is centrally connected .to a bell-crank lever I2 which controls a toothed segment l3 pivotally mounted at H}. The transmission of the angular displacements of the segment l3 to the disc I take place through the pinion l5, gear IE, pinion ll, gear i8 and pinion I9, the spindles being pivoted, on the one hand, on theplate I, and on the other hand, on an inner plate I connected to the first one by small columns such as 20. The spindle 8 extends forwardly of the plate totreceive'an indicating pointer 2|. The spindle 22 carries likewise, in this embodiment, a pointer 23. pointers can indicate different orders of the same units or difierent units (pressures and altitudes); The detail arrangement of the altimeter i moreover of no importance for the invention.

The coils 2 of the electro-magnets are fed with alternating current by connecting them to a suitable source through terminal 24 accessible from the front face of plate I which carries the dials or graduations over which move the indicating pointers 2| and 23. torque is exerted, for instance, in the, direction of the arrow (Fig. 3) on the disc l constantly taking up the play in the kinematic connection between the spindle 8 and the point 25 of 'the capsules.

The invention is defined in its main characteristic feature in the preamble to the present specification. a

The invention particularly concerns, by way of new industrial products, all apparatus and es-l pecially measuring apparatus; comprising a. rotor subjected to a constant returning,.torque, but. free to have, under another influencena movementdiflerent' from that which must beimparted thereto by; said constant returning torque. V

What I claim as my invention and desire to secure by Letters Patent is:

1. In an altimeter having a motion transmission multiplying mechanism, in combination: barometric capsules, indicating means, a mechnism comprising a train of gear for operatively connecting said capsules and said indicating means, a disc made of metal which is a good conductor of electricity coupled to the last gear of the train, and electromagnets havin their poles arranged on either side of said disc, each electromagnet having a shaded pole so that the mag- The constant returning netic flux is rendered asymmetric for producing a constant biasing torque.

. 2. In an apparatus of the class described, the combination of a driving member, a driven member, a train of gears connecting aid members, an electrical conductive disc drivingly connected to the end gear in said train adjacent said driven member, and electro-magnets having their poles arranged on either side of said disc, each electromagnet having a shaded pole so that the magnetic flux is rendered asymmetric for producing a constant returning torque acting on said driving member.

3. In an apparatus of the class described, the combination of a driving member, a driven member, a motion transmission multiplying mechanism having end portions respectively connected Th to said members, an electrical conductive disc drivingly connected to that end portion of said transmission adjacent said driven member, and at least one'electromagnet having its poles arranged on either side of said disc, said electromagnet having a shaded pole so that the magnetic flux is rendered asymmetric for producing a constant returning torque acting on said driving member.

4. In an apparatus of the class described, the combination of a driving member, a driven member, indicating means actuated by said driven member, a motion transmission multiplying mechanism having end portions respectively connected to said members, an electrical conductive disc drivingly connected to that end por tion of said transmission adjacent said driven member, and at least one electro-magnet having its poles arranged on either side of said disc, said electromagnet having a shaded pole so that the magnetic flux is rendered asymmetric for producing a constant returning torque acting on said driving member.

CHARLES HILAIRE HENRI RODANE' I'. 

